1. Field of the Invention
The present invention relates to a non-contact rotary movement sensor capable of independently implementing an output signal and a switching signal by corresponding two permanent magnets which have different magnetic flux directions respectively to a Hall device and to a lead switch or by corresponding one permanent magnet to the Hall device and using a contact switch as a switching signal.
2. Background of the Related Art
Generally, a rotary movement sensor is used for applying a amount of physical change of a continuously changing rotating body to an electric circuit, and a rotary position displacement sensor with a linear electric signal output function is used in various ways in each field of industry.
A rotary movement sensor is used mainly in position control of engine throttle valve of a vehicle, control of a steering wheel, height control of a vehicle, variable vane position control of an intake and exhaust valves of an engine, or speed control of an engine corresponding to the movement of an accelerator pedal. Also, a rotary movement sensor is used in control of the engine rotation speed of an agricultural machine or a heavy equipment and measurement of opening and closing of a fluid supply valve.
Many methods are used for measuring a rotary displacement, such as a potentiometer method which proportionally outputs the rotary angle of a rotating body which relatively moves to a fixed body, an encoder method which outputs as an optical code, an induced magnet measurement method, and an integrated circuit method using a Hall effect of a magnetic resistance.
A rotary movement sensor should be able to be used at the temperature of −40□ to 70□ which is required in rough working condition of a vehicle for commercial use or a heavy equipment and maintaining the durability which exceeds five million operation times which is required in an environmental condition such as dust and working.
A conventional contact type variable resistance sensor has weak points that the electric characteristic is not constant according to the temperature, and that the durability or the life span is shortened by the abrasion of the electric resistance track which is a contact part of a variable resistance and a brush. Especially, the contact type variable resistance sensor has a difficulty in working as the initially set electric resistance value changes during usage.
Korean registered patent No. 0504106 and No. 0458375 and U.S. Pat. No. 6,597,168 suggest non-contact type rotary movement sensors for making up for the weak points of a contact type rotary movement sensor. However, the non-contact type rotary movement sensors of the above-mentioned patents have the weak points that the production structure is complex as a balanced sensing bar with multiple openings is included in the configuration, and that switching is dependent on signal outputting.